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Posted: 11/15/2008 1:32:48 PM EDT
[Last Edit: 11/18/2008 7:14:56 PM EDT by 12_gauge]
I did not find this answered in the huge ACOG BDC thread, so please, no referrals. I already read it.

I have several questions.

How far off at 5,6,7, and 800m will the TA31-RCO-A4's BDC be using M193 instead of M855?

Trijicon claims it was developed using "2800fps and 62gr". Can someone confirm/deny this? THat is not correct vel. for a 20" barrel and M855.

Also, what is the difference between the TA31-RCOA4 and the ACOG TA31RCO-M150CP  

Really hoping for that Bullet guy from Trijicon to chime in here. IDEALLY the information I would like is the MOA distance between the BDC stata lines for the 2 ACOG's listed above so I can run my own numbers and answer my own questions using various MV/BC's.
Link Posted: 11/16/2008 6:22:30 PM EDT
Sorry, can't be of any help on the BDC question, but thought that I'd bump you back to the top, maybe Bullit will catch this.  On the other question, if I remember correctly the A4 version is for a 20" barrel and the M150CP is for a 14.5" barrel.
Link Posted: 11/18/2008 7:14:41 PM EDT
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??
Link Posted: 11/19/2008 7:47:36 AM EDT
Originally Posted By 12_gauge:
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA

TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA

Link Posted: 11/19/2008 9:08:32 AM EDT
Originally Posted By bullitt5172:


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA

TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA



Can you tell me which one of these the TA31F uses, or is it a seperate reticle all together? This is great information.



Link Posted: 11/19/2008 9:37:10 AM EDT
[Last Edit: 11/19/2008 9:37:42 AM EDT by bullitt5172]
Originally Posted By MPD142:
Originally Posted By bullitt5172:


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA

TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA


Can you tell me which one of these the TA31F uses, or is it a seperate reticle all together? This is great information.





TA31F would be very close (maybe the same, I would need to look it up) to the RCO-M4.
Link Posted: 11/19/2008 11:40:24 AM EDT
[Last Edit: 11/19/2008 11:40:49 AM EDT by 12_gauge]
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA


TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA



What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  
Link Posted: 11/19/2008 11:48:45 AM EDT
[Last Edit: 11/19/2008 11:50:14 AM EDT by bullitt5172]
Originally Posted By 12_gauge:
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA


TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA



What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  


As I mentioned, these are only approximations as I cannot give out the actual MOA dimensions.  Our reticles are designed around the M855 round and ballistic data given to us by the military as well as our other customers.  Sorry if this doesn't help you, it works great for the Army and Marines

ETA - if you are using a 20" barrel use the A4.  I really don't think you will notice if the BDC is slightly off given the round you choose.
Link Posted: 11/19/2008 12:46:15 PM EDT
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA


TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA



What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  


As I mentioned, these are only approximations as I cannot give out the actual MOA dimensions.  Our reticles are designed around the M855 round and ballistic data given to us by the military as well as our other customers.  Sorry if this doesn't help you, it works great for the Army and Marines

ETA - if you are using a 20" barrel use the A4.  I really don't think you will notice if the BDC is slightly off given the round you choose.



I am coming up with around a meter off in elevation at 800m using tha A4 and the M855. Perhapse I am calculating things wrong.
Link Posted: 11/19/2008 12:49:56 PM EDT
Originally Posted By 12_gauge:
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Update:

After a lengthy discussion with Trijicon today, I found out:

Both the RCO A4 AND M4 use the same BDC.

They both use a 62gr bullet at 28XX.X fps (Yes there was a .X) So basically, 2900fps. and I assume M855 are used. This made no sense to me as Trijicon claims one is for a 20" and one a 14.5" barrel. I asked them what the difference is and he could not tell me. He said they both were based off of a 62gr bullet at 2900fps (the last time I called I got a similar answer, although they said 2870fps, so the guy rounded down that time I guess.)

Wierd. I guess this means the BDC matches M193 more than it does M855 according to my ballistics calculator.

Any thoughts/experiences? Bullit??


Sorry buddy, didn't see this until now.  Here are approximations for each reticle.  They are based on the same bullet but the reticles are different due to the barrel length.

TA31RCO-A4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       8 MOA
2ND HASHMARK                12 MOA
3RD HASHMARK (600M)     17 MOA
4TH HASHMARK                23 MOA
5TH HASHMARK                32 MOA


TA31RCO-M4
FROM TIP OF CHEVRON TO:
BOTTOM OF THE CHEVRON  5 MOA
1ST HASHMARK (400M)       9 MOA
2ND HASHMARK                14 MOA
3RD HASHMARK (600M)     20 MOA
4TH HASHMARK                28 MOA
5TH HASHMARK                38 MOA



What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  


As I mentioned, these are only approximations as I cannot give out the actual MOA dimensions.  Our reticles are designed around the M855 round and ballistic data given to us by the military as well as our other customers.  Sorry if this doesn't help you, it works great for the Army and Marines

ETA - if you are using a 20" barrel use the A4.  I really don't think you will notice if the BDC is slightly off given the round you choose.



I am coming up with around a meter off in elevation at 800m using tha A4 and the M855. Perhapse I am calculating things wrong.


I'll look into it further, I just pulled the info from the reticle print....
Link Posted: 11/19/2008 1:16:27 PM EDT
Originally Posted By 12_gauge:

What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  




The numbers bullitt5172 posted are almost dead on compared to the numbers my ballistics calculator cranks out.

Even shooting M193 through a 14.5" barrel isn't a factor on man sized targets until you go past 500m.

M193 through a 20" barrel? Get the A4 and stop worrying.
Link Posted: 11/19/2008 1:34:49 PM EDT
[Last Edit: 11/19/2008 1:47:25 PM EDT by 12_gauge]
Originally Posted By gregw45:
Originally Posted By 12_gauge:

What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  




The numbers bullitt5172 posted are almost dead on compared to the numbers my ballistics calculator cranks out.

Even shooting M193 through a 14.5" barrel isn't a factor on man sized targets until you go past 500m.

M193 through a 20" barrel? Get the A4 and stop worrying.


Ok, I am the retard here. ACOG=M, I am using Y. I will re-figure in M and I bet it will be pretty close to dead on. :(

Thanks Bullit for the info!!!

ETA:

At 600y/m pretty much any round is within MOA using the A$ ACOG and 20" barrel. Past 600, the only way to get anywhere near the BDC (within 2-3 MOA at 800) is to use M193 and use the ACOG in Y instead of M. That will keep you to within 1MOA of your target from 0-800 yards.
This was calculated using M193=3250/.243 and M855=3100/.304.

If I were to use M855 and calculate in meters, I would be roughly 2' off at 800m

If I use M193 and use y, I will be within about 6" at 800 yards. (Basically pretend the BDC is set for yards and not meters, use M193, and dont worry about it).
Link Posted: 11/19/2008 4:46:16 PM EDT
Originally Posted By 12_gauge:
Originally Posted By gregw45:
Originally Posted By 12_gauge:

What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  




The numbers bullitt5172 posted are almost dead on compared to the numbers my ballistics calculator cranks out.

Even shooting M193 through a 14.5" barrel isn't a factor on man sized targets until you go past 500m.

M193 through a 20" barrel? Get the A4 and stop worrying.


Ok, I am the retard here. ACOG=M, I am using Y. I will re-figure in M and I bet it will be pretty close to dead on. :(

Thanks Bullit for the info!!!

ETA:

At 600y/m pretty much any round is within MOA using the A$ ACOG and 20" barrel. Past 600, the only way to get anywhere near the BDC (within 2-3 MOA at 800) is to use M193 and use the ACOG in Y instead of M. That will keep you to within 1MOA of your target from 0-800 yards.
This was calculated using M193=3250/.243 and M855=3100/.304.

If I were to use M855 and calculate in meters, I would be roughly 2' off at 800m

If I use M193 and use y, I will be within about 6" at 800 yards. (Basically pretend the BDC is set for yards and not meters, use M193, and dont worry about it).


Whewww,, saves me having to go through the print again
Link Posted: 11/19/2008 5:20:36 PM EDT
Originally Posted By bullitt5172:
Originally Posted By 12_gauge:
Originally Posted By gregw45:
Originally Posted By 12_gauge:

What round is this supposed to even approximate? It comes close to matching NOTHING the military is using. At 800m that is 256" drop. M193 only drops 236" and M855 around 200". So what optic should I get for launching M193 or m855 through an A4 20" ? This is confusing  




The numbers bullitt5172 posted are almost dead on compared to the numbers my ballistics calculator cranks out.

Even shooting M193 through a 14.5" barrel isn't a factor on man sized targets until you go past 500m.

M193 through a 20" barrel? Get the A4 and stop worrying.


Ok, I am the retard here. ACOG=M, I am using Y. I will re-figure in M and I bet it will be pretty close to dead on. :(

Thanks Bullit for the info!!!

ETA:

At 600y/m pretty much any round is within MOA using the A$ ACOG and 20" barrel. Past 600, the only way to get anywhere near the BDC (within 2-3 MOA at 800) is to use M193 and use the ACOG in Y instead of M. That will keep you to within 1MOA of your target from 0-800 yards.
This was calculated using M193=3250/.243 and M855=3100/.304.

If I were to use M855 and calculate in meters, I would be roughly 2' off at 800m

If I use M193 and use y, I will be within about 6" at 800 yards. (Basically pretend the BDC is set for yards and not meters, use M193, and dont worry about it).


Whewww,, saves me having to go through the print again


Meh, I wish I could get my hands on the print, but it seems to be internal info only :(

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